View full sizePhoto provided by Doyle, Raizner law firmThis is a photo taken by an Indiana National Guard soldier showing the bags of sodium dichromate at the Qarmat Ali water treatment plant in Iraq in 2003.

Jury selection is scheduled to begin Tuesday in the case of a dozen Oregon National Guard soldiers who are suing defense contractor KBR Inc. in federal court in Portland. Here are a few questions and answers about the case, which is expected to last from four to six weeks.

Q: Why are the soldiers suing KBR?

A: The roots of the case stem from the soldiers' service in southern Iraq in 2003, a few months after the U.S.-led invasion. The Pentagon had hired KBR to restore Iraq's flow of oil, requiring the Houston-based company to repair many pieces of damaged oil-extraction infrastructure. Among KBR's projects was to restore the vandalized water-treatment plant at Qarmat Ali in southern Iraq.

The Oregon troops were assigned to provide security at the plant while KBR officials and technicians tried to get the plant running again.

One of the problems at Qarmat Ali was that bags of a chemical compound called sodium dichromate -- a powder used to limit corrosion -- were torn open and the powder apparently drifted through the air and stained the soil. Sodium dichromate contains a carcinogen called hexavalent chromium.

The soldiers, through their lawyers, accuse KBR of knowingly exposing them to danger through contact with the chemical, which can cause a variety of health problems.

Q: What does KBR say about that?

A: KBR contends that it didn't realize initially that sodium dichromate posed a hazard at Qarmat Ali, but as soon as it realized it did, it informed the Army Corps of Engineers, which oversaw the project. It also sought to remedy the problem by taking such steps as capping areas of discolored soil. It denies knowingly exposing the troops to an environmental hazard.

Q: Have the soldiers developed health problems?

A: Yes. One Oregon soldier stationed at Qarmat Ali, Sgt. Nicholas Thomas, died of complications from leukemia at age 21. One of the Oregon plaintiffs, Larry Roberta, has been weakened by a variety of debilitating respiratory and digestive problems. Others have complained of symptoms including nosebleeds, rashes, lung problems and immune system disorders. And an Indiana National Guard commander stationed at Qarmat Ali, Lt. Col. James Gentry, died of lung cancer.

A: That's the key question. KBR has pointed out that the harsh conditions of the Iraqi desert have caused a series of health problems for U.S. troops all over the country -- not just at Qarmat Ali. KBR's experts will argue it's impossible to link the soldiers' health problems to the presence of sodium dichromate at the water-treatment plant.

The soldiers' experts will testify how even brief exposures to hexavalent chromium can serious and often unseen health problems, among them one what expert calls "genetic transformation injury." Q: Are other soldiers besides these 12 suing KBR?

A: Yes. The Oregon case originally had 39 plaintiffs, but some have withdrawn and U.S. Magistrate Judge Paul Papak and the lawyers trimmed the first trial to a more manageable 12 soldiers. The others' cases can go forward when the first one is finished.

In addition, a parallel case in Texas, McManaway vs. KBR, was expected to go to trial first, but has been stayed pending an appeal by KBR on a point of law. At the moment, that case, which lists more than 100 plaintiffs, remains pending.

A: The Pentagon's contract with KBR to restore Iraq's oil contained broad legal protection for KBR. The company argues that this indemnification clause should cover its legal costs and protect it from damages in the lawsuits brought by the soldiers. The Army Corps of Engineers disagrees and says KBR's legal protection "does not extend to chemical and industrial hazards" at Qarmat Ali. Q: Will the Portland case settle things?

A: No. Even Judge Papak has said he expects the jury's verdict, whatever it is, to be appealed. And the Texas case and the other Oregon still are headed for trial.